Burner flame stability chamber

ABSTRACT

A burner body is disclosed for use in a gas burner assembly. The burner body includes a sidewall and a main gas conduit, the main gas conduit having an inlet and an outlet; a plurality of primary burner ports disposed within the sidewall so as to be in communication with the outlet of the main gas conduit; a simmer flame port disposed within the sidewall in a spaced relation with the primary burner ports for providing a reignition source therefore; and a stability chamber disposed within the burner body, wherein the stability chamber comprises at least a first expansion region and a second expansion region, wherein the second expansion region has a greater volume than the first expansion region.

BACKGROUND OF THE INVENTION

The subject matter disclosed herein relates to gas appliances, such asgas ranges, and more particularly, to stability chambers for use in suchgas appliances.

Atmospheric gas burners are often used as surface units in household gascooking appliances. A significant factor in the performance of gasburners is their ability to withstand airflow disturbances in thesurroundings, such as room drafts, rapid movement of cabinet doors, andrapid oven door manipulation. Manipulation of the oven door isparticularly troublesome because rapid openings and closings of the ovendoor often produce respective under-pressure and over-pressureconditions within the oven cavity. Since the flue, through whichcombustion products are removed from the oven, is sized to maintain thedesired oven temperature and is generally inadequate to supply asufficient air flow for re-equilibration, a large amount of air passesthrough or around the gas burners. In particular, pressure fluctuationsfrom, for example, cabinet or door openings, cause the structures toexpand or contract (e.g., the sheet metal deflects) and this structuralmovement pumps air into adjacent cavities, causing the temporary underor over pressure conditions. This surge of air around the gas burners,due to over pressure or under pressure conditions in the oven cavity, isdetrimental to the flame stability of the burners and extinguish theflames. This flame stability problem is particularly evident in sealedgas burner arrangements, referring to the lack of an opening in thecooktop surface around the base of the burner to prevent spills fromentering the area beneath the cooktop.

Flame instability is caused by the low pressure drop of the fuel/airmixture passing through the burner ports of a typical rangetop burner.Although there is ample pressure available in the fuel, the pressureenergy is used to accelerate the fuel to the high injection velocityrequired for primary air entrainment. Relatively little of this pressureis recovered at the burner ports. A low pressure drop across the portsallows pressure disturbances propagating through the ambient to easilypass through the ports, momentarily drawing the flame towards the burnerhead and leading to thermal quenching and extinction.

An additional problem is that rapid adjustments of the fuel supply to agas burner from a high burner input rate to a low burner input rateoften will cause flame extinction when the momentum of the entrained airflow continues into the burner even though fuel has been cut back,resulting in a momentary drop in the fuel/air ratio, causing extinction.

A number of techniques have been proposed or suggested for improvingstability performance. U.S. Pat. No. 5,133,658, for example, employs anexpansion chamber to improve flame stability. The disclosed gas burnershave a plenum ahead of a number of main burner ports. An expansionchamber inlet is located in the plenum, adjacent the main flame ports.When a negative pressure disturbance enters the burner (suction, forexample, from the opening of an oven door), the pressure drop and flowvelocity through the main burner ports are momentarily reduced causingunwanted extinction of the main burner flames. The expansion chamberflame, however, is less susceptible to extinction due to the dampingeffect described in earlier art. Although such gas burners having anexpansion chamber provide somewhat improved stability performance atsimmer settings, disturbances continue to cause unwanted extinction.Furthermore, these expansion chambers have excessively large flames athigher burner input rates.

U.S. Pat. No. 5,800,159 overcomes the issue of excessively large flamesusing a stability chamber that is insensitive to turn-down. The flamefrom the stability chamber port, however, is dissimilar to the flamesfrom the other ports and gives the burner a non-symmetric flameappearance. In addition, stability chambers have an inherently lazyplume of gas exiting the chamber during operation, due to the slowvelocity of the fuel mixture exiting the chamber. The slow velocity ofthe fuel mixture reduces the kinetic energy of the flame and hence theability to entrain secondary air. Drafts, whether induced by the localgas flow of the burner itself or by external influences such as roomdrafts or drafts induced by the burner exhaust rising, can push or pullthe lazy plume exiting the chamber into a flame from an adjacent burnerport. When this occurs, the two flames tend to coalesce and becomestarved for air locally at the relatively higher flow rates. This, inturn, causes this plume of flame to reach longer for more air andimpinge on cool surrounding surfaces such as the cookware above theburner. The cool surfaces quench the flame, preventing completecombustion, and carbon or soot formation may occur. To reduce thistendency to coalesce, the distance between the stability chamber and theadjacent ports is increased. However, when this is done, it becomes moredifficult for the chamber's flame to reignite the adjacent ports afteran unwanted flame extinction due to the larger distance between flames.

Thus, there remains a need for an improved atmospheric gas burner thatis better able to withstand airflow disturbances, especially during lowburner input rates. Yet another need exists for stability chambers thatimprove the ability of the chamber to mechanically relight extinguishedflames of the adjacent flame ports in the burner at low flow rates,without sacrificing performance at high flow rates.

BRIEF DESCRIPTION OF THE INVENTION

As described herein, the exemplary embodiments of the present inventionovercome one or more disadvantages known in the art.

One aspect of the present invention relates to a burner body for use ina gas burner assembly. The burner body comprises: a sidewall and a maingas conduit, the main gas conduit having an inlet and an outlet; aplurality of primary burner ports disposed within the sidewall so as tobe in communication with the outlet of the main gas conduit; a simmerflame port disposed within the sidewall in a spaced relation with theprimary burner ports for providing a reignition source therefore; and astability chamber disposed within the burner body, wherein a firstinterior region of said stability chamber has a primary expansion anglesubstantially between said main gas conduit and said sidewall andwherein a second exterior region of said stability chamber has asecondary expansion angle substantially along said sidewall and whereinsaid secondary expansion angle is greater than said primary expansionangle.

Another aspect of the present invention relates to a gas cookingappliance comprising such a burner body.

Yet another aspect of the present invention relates to a stabilitychamber for use within a burner body of a gas burner assembly. Thestability chamber includes a first interior region having a primaryexpansion angle substantially between an interior tubular main gasconduit and an exterior sidewall of said burner body; and a secondexterior region having a secondary expansion angle substantially alongsaid sidewall and wherein said secondary expansion angle is greater thansaid primary expansion angle.

Advantageously, illustrative embodiments of the present inventionprovide the ability to improve the ability of the stability chamber tomechanically relight extinguished flames of adjacent flame ports at lowflow rates, without sacrificing performance at high flow rates.

These and other aspects and advantages of the present invention willbecome apparent from the following detailed description considered inconjunction with the accompanying drawings. It is to be understood,however, that the drawings are designed solely for purposes ofillustration and not as a definition of the limits of the invention, forwhich reference should be made to the appended claims. Moreover, thedrawings are not necessarily drawn to scale and, unless otherwiseindicated, they are merely intended to conceptually illustrate thestructures and procedures described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is an exploded perspective view of a prior art as burner assemblyincorporating a stability chamber to improve stability performance;

FIG. 2 is a cross-sectional plan view through line 2-2 of FIG. 1;

FIG. 3 illustrates the burner body of FIGS. 1 and 2 in further detail;

FIG. 4 illustrates an exemplary burner body in accordance with thepresent invention;

FIG. 5 is a top, sectional view of the exemplary burner body of FIG. 4;

FIGS. 6A and 6B illustrate the conventional stability chamber of FIG. 3and exemplary stability chamber of FIG. 4, respectively, when operatingat higher flow rates; and

FIGS. 7A and 7B illustrate the conventional stability chamber of FIG. 3and exemplary stability chamber of FIG. 4, respectively, when operatingat lower flow rates.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS OF THE INVENTION

One or more illustrative embodiments of the invention will be describedbelow in the context of an oven appliance. However, it is to beunderstood that embodiments of the invention are not intended to belimited to use with any particular gas appliance. Rather, embodiments ofthe invention may be applied to and deployed in any other suitableenvironment in which it would be desirable to relight extinguishedflames of adjacent flame ports in a gas burner.

As illustratively used herein, the term “appliance” is intended to referto a device or equipment designed to perform one or more specificfunctions. This may include, but is not limited to, equipment forconsumer use, e.g., a gas range on a freestanding oven. This mayinclude, but is not limited to, any equipment that is useable inhousehold or commercial environments.

While the methods and apparatus are herein described in the context of agas-fired cooktop, as set forth more fully below, it is contemplatedthat the herein described methods and apparatus may find utility inother applications, including, but not limited to, gas heater devices,gas ovens, gas kilns, gas-fired meat smoker devices, and gas barbecues.In addition, the principles and teachings set forth herein may findequal applicability to combustion burners for a variety of combustiblefuels. The description below is therefore set forth only by way ofillustration rather than limitation, and any intention to limit practiceof the herein described methods and apparatus to any particularapplication is expressly disavowed.

FIG. 1 is an exploded perspective view of a prior art gas burnerassembly 10 incorporating a stability chamber to improve stabilityperformance, and FIG. 2 is a cross-sectional plan view through line 2-2of FIG. 1. An atmospheric gas burner assembly 10 includes a burner body12 having a frustum-shaped solid base portion 14 and a cylindricalsidewall 16 extending axially from the periphery of base portion 14, asshown in the illustrative embodiment of FIGS. 1 and 2. A main gasconduit 18 having an entry area 19 and a burner throat region 20 is opento the exterior of burner body 12 and defines a passage which extendsaxially through the center of burner body 12 to provide fuel/air flowalong path “A” (FIG. 2) to burner assembly 10. As used herein, the term“gas” refers to a combustible gas or gaseous fuel mixture.

Burner assembly 10 is attached, in a known manner, to a support surfaceof a gas cooking appliance such as a range or a cooktop. A cap 22 isdisposed over the top of burner body 12, defining therebetween anannular main fuel chamber 24, an annular diffuser region 25 (FIG. 2),and a stability chamber 26, typically wedge-shaped. A toroidal-shapedupper portion 27 of burner body 12, immediately bordering burner throat20, in combination with cap 22 defines annular diffuser region 25therebetween. Cap 22 can be fixedly attached to sidewall 16 (FIG. 1) orcan simply rest on sidewall 16 for easy removal. While one type ofburner is described and illustrated, the instant invention is applicableto other types of burners, such as stamped aluminum burners andseparately mounted orifice burners.

As shown in FIG. 2, annular main fuel chamber 24 is defined by an outersurface 28 of toroidal shaped upper surface 27, an inner surface 29 ofsidewall 16 (FIG. 1), an upper surface 30 of base portion 14, and cap22. A plurality of primary burner ports 32 are disposed in sidewall 16of burner body 12 so as to provide a path to allow fluid communicationwith main fuel chamber 24, each primary burner port 32 being adapted tosupport a respective main flame 33 (FIG. 2). Primary burner ports 32 aretypically, although not necessarily, evenly spaced about sidewall 16. Asused herein, the term “port” refers to an aperture of any shape fromwhich a flame may be supported.

At least one simmer flame port 34 is disposed in sidewall 16 (FIG. 1) ofburner body 12 so as to provide a path to allow fluid communication withstability chamber 26. Simmer flame port 34 is substantially isolatedfrom main fuel chamber 24 and is adapted to support a simmer flame 35.Simmer flame port 34 is adjacent to primary burner ports 32 to provide are-ignition source to primary burner ports 32 if flameout occurs. Whilea single simmer flame port 34 is shown in the drawings, the presentinvention may include one or more additional simmer flame ports 34.Typically, simmer flame port 34 has an open area five to fifteen timeslarger than a respective primary burner port 32.

A gas feed conduit 36 (FIG. 2) comprises a coupling 38 disposed on oneend for connection to a gas source 40 via a valve 42 (shownschematically in FIG. 2). Valve 42 is controlled in a known manner by acorresponding control knob on the gas cooking appliance to regulate theflow of gas from gas source 40 to gas feed conduit 36. The other end ofgas feed conduit 36 is provided with an injection orifice 44. Injectionorifice 44 is aligned with main gas conduit 18 so that fuel, dischargedfrom injection orifice 44, and entrained air are supplied to main fuelchamber 24 and stability chamber 26 via main gas conduit 18 along path“A” of FIG. 2.

As shown in FIGS. 1 and 2, stability chamber 26 is substantiallyisolated from main fuel chamber 24 such that stability chamber 26 is notin immediate fluid communication with main fuel chamber 24 and istherefore relatively independent of primary burner ports 32. Stabilitychamber 26 is defined on each side by a pair of radially extendingbaffles 50 a and 50 b (FIG. 1), on the bottom by an upper surface 46(FIG. 2) of burner body 12, and on the top by cap 22. An end wall 52positioned proximate burner throat 20 further defines stability chamber26 so as to substantially isolate stability chamber 26 from main fuelchamber 24. In an exemplary embodiment, as best shown in FIG. 2, uppersurface 46 of burner body 12 is configured such that stability chamber26 has a shallow depth at the narrow end of stability chamber 26 closestto burner throat 20 and transitions to a deeper, wider section whenclosest to simmer flame port 34.

In the embodiment of FIGS. 1 and 2, stability chamber 26 furthercomprises two stability inlets 60 a and 60 b. Stability inlets 60 a, 60b are disposed within respective baffles 50 a, 50 b such that stabilityinlets 60 a, 60 b are positioned so as to be substantially symmetricalon each side of stability chamber 26 proximate end wall 52 andcorrespondingly proximate burner throat 20. Stability inlets 60 a, 60 bare substantially perpendicular to the direction of the flow of gasradially outward from burner throat 20 and are tangentially fed thefuel/air mixture by static pressure at that location, as discussedbelow. The stability chamber 26 may include one or more stabilityinlets. Stability inlet(s) 60 a, 60 b are positioned at burner throat20. This arrangement improves stability performance by permitting aneffectively smaller stability chamber inlet to be utilized whileretaining sufficient gas flow. Additionally, an aesthetically pleasantreduced stability flame size is created at higher burner input rates.For a more detailed discussion of a prior art gas burner assembly 10incorporating a stability chamber, see, for example, U.S. Pat. No.5,800,159, incorporated by reference herein.

FIG. 3 illustrates the burner body 12 of FIGS. 1 and 2 in furtherdetail. As shown in FIG. 3, the exemplary burner body 12 comprises afrustum-shaped solid base portion 14 and a cylindrical sidewall 16extending axially from the periphery of base portion 14. A main gasconduit 18 having a burner throat region 20 is open to the exterior ofburner body 12 and defines a passage which extends axially through thecenter of burner body 12 to provide fuel/air flow as discussed above inconjunction with FIG. 2.

As shown in FIG. 3, stability chamber 26 is substantially isolated frommain fuel chamber 24 such that stability chamber 26 is not in immediatefluid communication with main fuel chamber 24 and is thereforerelatively independent of primary burner ports 32. Stability chamber 26is defined on each side by a pair of radially extending baffles 50 a and50 b, on the bottom by an upper surface 46 of burner body 12, and on thetop by a cap (not shown in FIG. 3). An end wall 52 positioned proximateburner throat 20 further defines stability chamber 26 so as tosubstantially isolate stability chamber 26 from main fuel chamber 24. Asshown in FIG. 3, upper surface 46 of burner body 12 is configured suchthat stability chamber 26 has a shallow depth at the narrow end ofstability chamber 26 closest to burner throat 20 and transitions to adeeper, wider section when closest to the broader end of stabilitychamber 26, adjacent the simmer flame port 34 (not shown in FIG. 3).

FIG. 4 illustrates an exemplary burner body 112 in accordance with thepresent invention. As shown in FIG. 4, the exemplary burner body 112comprises a frustum-shaped solid base portion 114 and a cylindricalsidewall 116 extending axially from the periphery of base portion 114,in a similar manner to FIG. 3. A main gas conduit 118 having a burnerthroat region 120 is open to the exterior of burner body 112 and definesa passage which extends axially through the center of burner body 112 toprovide fuel/air flow as discussed above in conjunction with FIG. 2.

As shown in FIG. 4, a stability chamber 126 in accordance with thepresent invention is substantially isolated from main fuel chamber 124such that stability chamber 126 is not in immediate fluid communicationwith main fuel chamber 124 and is therefore relatively independent ofprimary burner ports 132, in a similar manner to FIG. 3. A firstexpansion region of stability chamber 126 is defined on each side by apair of radially extending baffles 150 a and 150 b, on the bottom by anupper surface 146 of burner body 112, and on the top by a cap (not shownin FIG. 3). An end wall 152 positioned proximate burner throat 120further defines stability chamber 126 so as to substantially isolatestability chamber 126 from main fuel chamber 124. As shown in FIG. 4,upper surface 146 of burner body 112 is configured such that stabilitychamber 126 has a shallow depth at the narrow end of stability chamber126 closest to burner throat 120 and transitions to a deeper, widersection when closest to the broader end of stability chamber 126,adjacent the simmer flame port 134 (not shown in FIG. 4).

According to one aspect of the present invention, as discussed furtherbelow in conjunction with FIG. 5, stability chamber 126 has a furtherexpansion region with a wider section when closest to the broader end ofstability chamber 126, adjacent the simmer flame port 134 (not shown inFIG. 4). In this manner, the disclosed stability chamber 126 adds anadditional volume expansion in an additional expansion region 180 (FIG.5) at the exit of the chamber 126. This exit expansion allows thechamber flame to expand laterally under low flow conditions whileminimizing the lateral expansion at higher flow rates since the flamevelocity at the exit of the stability chamber 126 has a greater radialmagnitude relative to the rate of lateral expansion when the flow rateis at a higher firing rate. As discussed further below, the additionalvolume expansion 180 at the exit of the chamber 126 may result from theend portion of the chamber side wall forming a second expansion anglerelative to the primary chamber wall expansion angle, or it may be aradius at the exit. This feature reduces the effective distance betweenthe chamber walls and the adjacent ports at low flows, while maintaininga higher true distance between those geometries as high flows whereseparation is needed. In other words, at higher flow rates, the exitinggas overlooks the additional expansion, while at lower flow rates, theexiting gas expands further.

FIG. 5 is a top, sectional view of the exemplary burner body 112 of FIG.4. As shown in FIG. 5, the stability chamber 126 has a primary expansionangle 170, in a similar manner to the conventional stability chambers 26discussed above, as well as a secondary expansion angle 175, associatedwith the additional expansion region 180 provided by the presentinvention. As shown in FIG. 5, the secondary expansion angle 175 isgreater than the primary expansion angle 170. In one exemplaryembodiment, the primary expansion angle 170 can be, for example, 20degrees, and the secondary expansion angle 175 can be, for example, 120degrees.

In addition, the additional expansion region 180 of the presentinvention is also characterized by a first distance to adjacent port190, which is the distance between the end of additional expansionregion 180 and the adjacent main flame port 160, and a second distanceto adjacent port 195, which is the distance between the baffles 150 aand 150 b of the stability chamber 126 and the adjacent main flame port160, as shown in FIG. 5. In one exemplary embodiment, the first distanceto adjacent port 190 can be, for example, 0.150 inches and the seconddistance to adjacent port 195 can be, for example, 0.09 inches.

The distinction between “higher flow rates” and “lower flow rates” is aparametric value that is proportional to the size of the burner. Lowflow rates are typically approximately 1/10 to 1/12 of the maximumburner rate. For example, a burner that is sized to produce 12,000Btu/hr at maximum flow would be capable of supporting a low flow rate of1000 to 1,200 Btu/hr with an effective stability chamber. Without aneffective stability chamber, the burner would be able to support a ratioof ⅙ of the maximum burner rate, so the burner would not be able tosupport a flow rate that is significantly lower than approximately 2000Btu/hr. Thus, any flow rate higher than ⅙ of the maximum burner rate isconsidered a high flow rate.

FIGS. 6A and 6B illustrate the prior art stability chamber 26 of FIG. 3and stability chamber 126 of the present invention (FIG. 4),respectively, when operating at higher flow rates. As indicated above,at higher flow rates, the disclosed stability chamber 126 minimizes thelateral expansion at higher flow rates since the flame velocity at theexit of the stability chamber 126 has a greater radial magnituderelative to the rate of lateral expansion when the flow rate is at ahigher firing rate. The additional expansion region 180 maintains ahigher true distance between those geometries at high flows whereseparation is needed. Thus, at higher flow rates, the exiting gasoverlooks the additional expansion region 180, in a similar manner tothe conventional stability chamber 26.

Generally, gas flames expand due to the inherent expansion of combustionby-products and secondary effects of buoyancy and air entrainment. Thisexpansion is shown in FIGS. 6A and 6B as a vector, VL. There is also avelocity vector Vn due to the momentum of the gas mixture being ejectedfrom the burner ports. As shown in FIGS. 6A and 6B, at high flow rates,the velocity Vn is dominant and the secondary expansion angle of theexemplary additional expansion region 180 has negligible effect on theseparation of the chamber flame relative, as shown by gap 198.

FIGS. 7A and 7B illustrate the prior art stability chamber 26 of FIG. 3and stability chamber 126 of the present invention (FIG. 4),respectively, when operating at lower flow rates. As indicated above,the exit expansion of the additional expansion region 180 allows thechamber flame to expand further laterally under low flow conditions. Theadditional volume expansion 180 reduces the effective distance 198between the chamber walls 150 a, 150 b and the adjacent ports 160 at lowflow rates. Thus, as shown in FIG. 7B at lower flow rates, the exitinggas expands further than with the prior art stability chamber 26associated with FIG. 7A. As shown in FIG. 7B, at lower flow rates, thesecondary expansion of the additional expansion region 180 at thechamber exit further reduces the velocity Vn, increasing the expansionvector VL, thereby improving the cross-talk to flames of the adjacentports 160.

Thus, while there have been shown and described and pointed outfundamental novel features of the invention as applied to exemplaryembodiments thereof, it will be understood that various omissions andsubstitutions and changes in the form and details of the devicesillustrated, and in their operation, may be made by those skilled in theart without departing from the spirit of the invention. Moreover, it isexpressly intended that all combinations of those elements and/or methodsteps which perform substantially the same function in substantially thesame way to achieve the same results are within the scope of theinvention. Furthermore, it should be recognized that structures and/orelements and/or method steps shown and/or described in connection withany disclosed form or embodiment of the invention may be incorporated inany other disclosed or described or suggested form or embodiment as ageneral matter of design choice. It is the intention, therefore, to belimited only as indicated by the scope of the claims appended hereto.

What is claimed is:
 1. A burner body for use in a gas burner assembly,said burner body comprising: a sidewall and a main gas conduit, saidmain gas conduit comprising an inlet and an outlet; a plurality ofprimary burner ports disposed within said sidewall so as to be incommunication with said outlet of said main gas conduit; a simmer flameport disposed within said sidewall in a spaced relation with saidprimary burner ports for providing a reignition source therefore; and astability chamber disposed within said burner body, wherein a firstinterior region of said stability chamber has a primary expansion anglesubstantially between said tubular main gas conduit and said sidewalland wherein a second exterior region of said stability chamber has asecondary expansion angle substantially along said sidewall and whereinsaid secondary expansion angle is greater than said primary expansionangle.
 2. The burner body of claim 1, wherein said second exteriorregion comprises a radius at an exit of said stability chamber.
 3. Theburner body of claim 1, wherein said stability chamber is defined oneach side by a pair of radially extending baffles, on the bottom by anupper surface of said burner body, on the top by a cap, and by anend-wall at said outlet so as to extend from said outlet to said simmerflame port.
 4. The burner body of claim 3, wherein said upper surface isconfigured such that a depth of said stability chamber at an end of saidstability chamber closest said outlet has a value less than a depth ofsaid stability chamber at an end closest to said simmer flame port. 5.The burner body of claim 1, wherein said stability chamber minimizes alateral expansion of a gas at relatively high flow rate.
 6. A gascooking appliance comprising a burner body, said burner body comprising:a sidewall and a main gas conduit, said main gas conduit comprising aninlet and an outlet; a plurality of primary burner ports disposed withinsaid sidewall so as to be in communication with said outlet of said maingas conduit; a simmer flame port disposed within said sidewall in aspaced relation with said primary burner ports for providing areignition source therefore; and a stability chamber disposed withinsaid burner body, wherein a first interior region of said stabilitychamber has a primary expansion angle substantially between said maingas conduit and said sidewall and wherein a second exterior region ofsaid stability chamber has a secondary expansion angle substantiallyalong said sidewall and wherein said secondary expansion angle isgreater than said primary expansion angle.
 7. The gas cooking applianceof claim 6, wherein said second exterior region comprises a radius at anexit of said stability chamber.
 8. The gas cooking appliance of claim 6,wherein said stability chamber is defined on each side by a pair ofradially extending baffles, on the bottom by an upper surface of saidburner body, on the top by a cap, and by an end-wall at said outlet soas to extend from said outlet to said simmer flame port.
 9. The gascooking appliance of claim 8, wherein said upper surface is configuredsuch that a depth of said stability chamber at an end of said stabilitychamber closest said outlet has a value less than a depth of saidstability chamber at an end closest to said simmer flame port.
 10. Thegas cooking appliance of claim 6, wherein said stability chamberminimizes a lateral expansion of a gas at relatively high flow rate. 11.A stability chamber for use within a burner body of a gas burnerassembly, said stability chamber comprising: a first interior regioncomprising a primary expansion angle substantially between an interiortubular main gas conduit and an exterior sidewall of said burner body;and a second exterior region comprising a secondary expansion anglesubstantially along said sidewall and wherein said secondary expansionangle is greater than said primary expansion angle.
 12. The stabilitychamber of claim 11, wherein said second exterior region comprises aradius at an exit of said stability chamber.
 13. The stability chamberof claim 11, wherein said stability chamber is defined on each side by apair of radially extending baffles, on the bottom by an upper surface ofsaid burner body, on the top by a cap, and by an end-wall at said outletso as to extend from said outlet to said simmer flame port.
 14. Thestability chamber of claim 13, wherein said upper surface is configuredsuch that a depth of said stability chamber at an end of said stabilitychamber closest said outlet has a value less than a depth of saidstability chamber at an end closest to said simmer flame port.
 15. Thestability chamber of claim 11, wherein said stability chamber minimizesa lateral expansion of a gas at relatively high flow rate.